package com.peans.common.utils;

import java.math.BigDecimal;

public enum LBSUtils {

	;
	private static double EARTH_RADIUS = 6378.137;

	private static double rad(double d) {
		return d * Math.PI / 180.0;
	}

	public static double getDistance(double lat1, double lng1, double lat2,
			double lng2) {
		double radLat1 = rad(lat1);
		double radLat2 = rad(lat2);
		double a = radLat1 - radLat2;
		double b = rad(lng1) - rad(lng2);
		double s = 2 * Math.asin(Math.sqrt(Math.pow(Math.sin(a / 2), 2)
				+ Math.cos(radLat1) * Math.cos(radLat2)
				* Math.pow(Math.sin(b / 2), 2)));
		s = s * EARTH_RADIUS;
		BigDecimal d = new BigDecimal(s);
		double f = d.setScale(2, BigDecimal.ROUND_HALF_UP).doubleValue();
		return f;
	}
	
	public static String getDistanceStr(double lat1, double lng1, double lat2,
			double lng2) {
		return LBSUtils.getDistance(lat1, lng1, lat2, lng2) + "km";
	}

}
